Heat transfer component and het transfer process

ABSTRACT

A heat transfer component and heat transfer process are disclosed. The heat transfer component includes thermally-responsive features positioned along a surface of the heat transfer component. The thermally-responsive features deploy from or retract toward the surface in response to a predetermined temperature change. The deploying from or the retracting toward of the thermally-responsive features increases or decreases a rate of heat transfer between a flow along the surface and the surface. The heat transfer process includes providing a heat transfer component having thermally-responsive features positioned along a surface of the heat transfer component; and increasing or decreasing a heat transfer rate between the surface and a flow by deploying the thermally-responsive features from or the retracting the thermally-responsive features toward the surface in response to a predetermined temperature change.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. Utility application Ser. No. 13/436,420, filed Mar. 30, 2012, and entitled “COMPONENTS HAVING TAB MEMBERS,” the disclosure of which is incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention is directed to components and processes of using components. More particularly, the present invention is directed to heat transfer components and heat transfer processes.

BACKGROUND OF THE INVENTION

Heat transfer is an important component of several operations. Increased control of heat transfer between surfaces and fluids contacting the fluids permits increased efficiency in turbine operations, permits increased efficiency in engine operations, permits increased cooling in cooling operations, and/or permits increased properties for a variety of systems operating based upon differential temperatures.

The heat transfer coefficient for liquids and gases flowing through pipes in heat exchangers tends to be limited due to a fluid boundary layer close to the pipe wall that is stagnant or moves at a slow speed, thus acting as an insulating layer. This boundary layer decreases heat transfer, which can decrease efficiency of operations relying upon differential temperatures. Known heat transfer surfaces do not provide selective turbulation and, thus, are not capable of selectively increasing or decreasing the fluid boundary layer, thereby limiting control of heat transfer.

A heat transfer component and a heat transfer process that do not suffer from one or more of the above drawbacks would be desirable in the art.

BRIEF DESCRIPTION OF THE INVENTION

In an exemplary embodiment, a heat transfer component includes thermally-responsive features positioned along a surface of the heat transfer component. The thermally-responsive features deploy from or retract toward the surface in response to a predetermined temperature change. The deploying from or the retracting toward of the thermally-responsive features increases or decreases a rate of heat transfer between a flow along the surface and the surface.

In another exemplary embodiment, a heat exchanger includes thermally-responsive features positioned along a surface of the heat exchanger, the thermally-responsive features having a first metallic layer and a second metallic layer. The thermally-responsive features deploy from or retract toward the surface in response to a predetermined temperature change. The deploying from or the retracting toward of the thermally-responsive features increases or decreases turbulation of a flow along the surface, thereby increasing or the decreasing velocity of the flow, acceleration of the flow, a proportion of turbulent flow within the flow, a proportion of laminar flow within the flow, a proportion of transitional flow within the flow, a depth of a boundary layer adjacent to the surface, or a combination thereof.

In another exemplary embodiment, a heat transfer process includes providing a heat transfer component having thermally-responsive features positioned along a surface of the heat transfer component, and increasing or decreasing a rate of heat transfer between the surface and a flow by deploying the thermally-responsive features from or the retracting the thermally-responsive features toward the surface in response to a predetermined temperature change.

Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an exemplary component according to an embodiment of the disclosure.

FIG. 2 is a schematic view of an exemplary component according to an embodiment of the disclosure.

FIG. 3 is a schematic view of an exemplary component according to an embodiment of the disclosure.

FIG. 4 is a schematic view of a portion of an exemplary component according to an embodiment of the disclosure.

FIG. 5 is a schematic view of a portion of an exemplary component according to an embodiment of the disclosure.

FIG. 6 is a schematic view of a portion of an exemplary heat exchanger according to an embodiment of the disclosure.

FIG. 7 is a schematic view of a portion of an exemplary condenser according to an embodiment of the disclosure.

FIG. 8 is a schematic view of a portion of an exemplary heat pipe according to an embodiment of the disclosure.

FIG. 9 is a schematic view of an exemplary regenerator according to an embodiment of the disclosure.

FIG. 10 is a schematic view of an exemplary evaporative cooler according to an embodiment of the disclosure.

FIG. 11 is a schematic view of an exemplary pattern for thermally-responsive features according to an embodiment of the disclosure.

FIG. 12 is a schematic view of an exemplary pattern for thermally-responsive features according to an embodiment of the disclosure.

FIG. 13 is a schematic view of an exemplary pattern for thermally-responsive features according to an embodiment of the disclosure.

FIG. 14 is a schematic view of an exemplary pattern for thermally-responsive features according to an embodiment of the disclosure.

Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts.

DETAILED DESCRIPTION OF THE INVENTION

Provided is an exemplary heat transfer component and a heat transfer process. Embodiments of the present disclosure, for example, in comparison to components not having features of the heat transfer component, permit increased or decreased rate of heat transfer, permit selective heat transfer, permit flow characteristics to be modified, permit formation of selective turbulent flow or turbulation, permit a fluid boundary layer to be selectively increased or decreased in depth, permit a gradient of heat transfer properties, or combinations thereof.

Referring to FIG. 1, in one embodiment, a heat transfer component 1010 includes a structure 10 having thermally-responsive features 20 (for example, tab members). The heat transfer component 1010 is any suitable component benefiting from increased or decreased rate of heat transfer, other components with a surface 13 or heat transfer interface along the flow path 19, or a combination thereof. As used herein, the phrase “thermally-responsive” refers to being capable of physical movement based upon a predetermined temperature change in a direction beyond expansion and contraction. For example, such directions include, but are not limited to, those associated with flexing, bending, raising, retracting or combinations thereof. The thermally-responsive features 20 deploy from or retract toward the surface 13 of the structure 10 in response to a predetermined temperature change.

In one embodiment, the thermally-responsive features 20 are capable of physical movement because a first layer 12, which may coincide with the surface 13 and/or be proximal to the surface 13 in comparison to a second layer 14, includes a first metal or metallic material and the first layer 12 is directly or indirectly positioned on the second layer 14 having a second metal or metallic material, the first metal or metallic material having a different composition than the second metal or metallic material. The first layer 12 and the second layer 14 are secured by any suitable manner, such as, by diffusion bonding, electron beam welding, laser welding, brazing, spraying, sputtering, ion plasma processing, melt-solidification, direct writing, laser cladding, plating, powder melting, laser sintering, galvanizing, or a combination thereof. Suitable spraying techniques include, but are not limited to, thermal spraying, chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma spraying, detonation spraying, wire arc spraying, flame spraying, high velocity oxy-fuel coating spraying (HVOF), warm spraying, cold spraying, and combinations thereof.

The structure 10 is any suitable structure coated with at least one dissimilar metallic layer. The first layer 12 and/or the second layer 14 of the structure 10 include(s) any suitable metal or metallic material. Suitable such alloys are selected from the group consisting of nickel, iron, cobalt, stainless steel, aluminum, copper, magnesium, gold, platinum, MCrAlY (wherein M is Ni, Co, Fe, or combinations thereof), alloys thereof, 304 stainless steel substrate (available from AK Steel Corporation, West Chester, Ohio), and combinations thereof. Other suitable materials include, but are not limited to, CrMoV and NiCrMo (for example, having a low thermal expansion coefficient of about 6), INCONEL® materials, such as, but not limited to, INCONEL®625, INCONEL®718 (available from Special Metals Corporation, Huntington, W. Va.), (for example, having a medium thermal expansion coefficient of about 7), stainless steels, such as, but not limited to, 316 stainless steel (UNS 531600, an austenitic chromium, nickel stainless steel containing molybdenum) or 304 stainless steel (UNS 530400, a variation of the basic 18-8 grade, Type 302, with a higher chromium and lower carbon content) (available from AK Steel, West Chester, Ohio) (for example, having a high coefficient of thermal expansion of approximately 9).

The first layer 12 and the second layer 14 have dissimilar thermal expansion coefficients. The difference in thermal expansion coefficients (α) between the first layer 12 and the second layer 14 allows the thermally-responsive features 20 to respond to the predetermined temperature change, whether induced or environmental. The first layer 12 has a first coefficient of thermal expansion (α₁) and the second layer 14 has a second coefficient of thermal expansion (α₂), the first coefficient of thermal expansion (α₁) and the second coefficient of thermal expansion (α₂) differ by a predetermined amount to achieve a desired response based upon the predetermined temperature change. Suitable differences include, but are not limited to, a difference of about 3%, about 5%, about 7%, about 10%, between about 3% and about 5%, between about 3% and about 7%, an order of magnitude of 1.1, an order of magnitude of 1.5, an order of magnitude of 2, an order of magnitude between 1.1 and 2, or any suitable combination, sub-combination, range, or sub-range thereof, an order of magnitude being based upon how much deflection is desired, given a predetermined temperature change, based upon bimetallic beam bending calculations for a given material set and feature/beam geometry.

In one embodiment, the thermally-responsive features 20 are positioned to deploy up away from the surface 13, for example, in a raising direction 32 as shown in FIGS. 1-3. Additionally or alternatively, the thermally-responsive features 20 are positioned to retract toward the surface 13 in a retracting direction 34 as shown in FIGS. 1-3. To deploy up away from the surface 13 in the raising direction 32, for example, toward an adjacent surface 30 to close a gap 42 and/or through a portion or all of a fluid boundary layer 33 (see FIG. 4) as is shown in FIGS. 1 and 3, and/or reduce air flow volume and/or rate in response to the predetermined temperature change being an increase in temperature, the first coefficient of thermal expansion (α₁) is greater than the second coefficient of thermal expansion (α₂). To retract toward the surface 13 in the retracting direction 34, for example, away from the adjacent surface 30 to create and/or increase the gap 42 and/or away from the fluid boundary layer 33 (see FIG. 4) as is shown in FIGS. 1 and 3, and/or increase air flow volume and/or rate in response to the predetermined temperature change being an increase in temperature, the first coefficient of thermal expansion (α₁) is less than the second coefficient of thermal expansion (α₂). In one embodiment, the thermally-responsive features 20, in response to the predetermined temperature, adjust in height 40 (see FIGS. 1-2), for example, from the surface 13, within a predetermined range, such as, between about 10% and about 50%, between about 15% and about 45%, between about 20% and about 30%, or any suitable combination, sub-combination, range, or sub-range therein.

In one embodiment, the thermally-responsive features 20 are formed by cutting or penetrating at least a portion 28 of the structure 10 and the second layer 14, thereby creating the thermally-responsive features 20 in the surface 13 of the structure 10. Suitable methods for forming plurality of thermally-responsive features 20, include, but are not limited to, laser surface sculpting, breaking, fracturing or disrupting a brittle layer, applying a pulsed laser, applying targeted mechanical shock and/or mechanical stress, or a combination thereof. In one embodiment, the thermally-responsive features 20 are sculpted into means for forming a pattern 1001, such as, but not limited to, rows or lines 1003 (see FIG. 11), dashed rows/lines 1005 (see FIG. 12), fish scales 1007 (see FIG. 13), zig-zags 1009 (see FIG. 14), slots or elongate holes, other desired patterns, or a combination thereof.

Referring to FIG. 2, in one embodiment, the heat transfer component 1010 restricts a flow path 19 and/or increases or otherwise modifies flow 16, for example, as is shown in FIGS. 4 and 5. As temperature increases resulting in the predetermined temperature change, the thermally-responsive features 20 reposition toward and/or press against the adjacent surface 30, for example, of a separate body 31 sealing and/or restricting the flow path 19 and/or extend partially or completely through the fluid boundary layer 33 increasing a proportion of the turbulent flow 35 in the flow 16 in comparison to other types of flow (such as, laminar flow 37 and/or transitional flow, not shown). In one embodiment, the heat transfer component 1010 acts as a turbulator for pipe flow, such as, a twisted-tape turbulator (for example, a twisted ribbon that forces fluid to move in a helicoidal path rather than in a straight line), a Brock turbulator (for example, a zig-zag folded ribbon), a wire turbulator (for example, an open structure of looped and entangled wires that extends over an entire pipe length), or a combination thereof. In one embodiment, the turbulent flow 35 in the flow 16 is more prevalent than other types of flow. Additionally or alternatively, the thermally-responsive features 20 increase and/or throttle the flow path 19. For example, as temperature increases resulting in the predetermined temperature change, the thermally-responsive features 20 retract toward the surface 13 of the sealing structure 10 and/or away from the adjacent surface 30 of separate body 31 and/or away from the fluid boundary layer 33, thereby increasing the rate and/or volume of the flow 16 through the flow path 19 and the gap 42.

Referring again to FIGS. 2 and 3, in one embodiment, the second layer 14 includes a first metallic layer 50 and a second metallic layer 52, the first metallic layer 50 being distal from the surface 13 in comparison to the second metallic layer 52. In further embodiments, the second layer 14 further includes a third metallic layer 54 and/or a fourth metallic layer 56 (see FIG. 3), the third metallic layer 54 being positioned opposite the first metallic layer on the second metallic layer 52 and the fourth metallic layer 56 being positioned proximal to the surface 13 in comparison to the third metallic layer 54. In one embodiment, the first metallic layer 50, the second metallic layer 52, the third metallic layer 54, the fourth metallic layer 56, or a combination thereof, have different thermal expansion coefficients and/or form at least a portion of the thermally-responsive features 20.

Referring again to FIG. 3, in one embodiment, the thermally-responsive features 20 include one or more layered portions 26, the layered portion(s) 26 including the first metallic layer 50, the second metallic layer 52, and the third metallic layer 54. In one embodiment, the first metallic layer 50 is a weaker or more brittle metallic layer than the second metallic layer 52 and/or the third metallic layer 54. As used herein, “brittle” refers to being less ductile. In one embodiment, the first metallic layer 50 is a material with a tensile elongation at failure of less than about 10%, a porosity between about 0% or 1% by volume and about 50% by volume, or a combination thereof. In a further embodiment, the first metallic layer 50 is configured to be broken when mechanical stress or other stress is applied.

The third metallic layer 54 is a strong metallic layer having a different coefficient of thermal expansion (α) than the second metallic layer 52. In one embodiment, the third metallic layer 54 is selected from a material having a coefficient of thermal expansion (α) that is up to about the same or about 20% different than the first metallic layer 50 and/or the second metallic layer 52. The 20% difference is either greater than or less than, depending on the desired movement of thermally-responsive features 20. Misfit strain (ε) is the difference between the coefficients of thermal expansion (α) for a temperature gradient and is calculated using the following equation:

ε=(α₁−α₂)ΔT

where ε is misfit strain; α₁ and α₂ are the coefficient of thermal expansion of two layers; and ΔT is the temperature gradient, which is the current temperature minus the reference temperature. The reference temperature is the temperature at which the thermally-responsive features 20 have no flexure or movement. In one embodiment, the predetermined temperature change results in a misfit strain of at least about 8%, for example, between the second metallic layer 52 and the third metallic layer 54.

Suitable examples of materials for the first metallic layer 50 include, but are not limited to, nickel-aluminum, titanium-aluminum, nickel-chromium carbide, cobalt-chromium carbide, alloys thereof and combinations thereof. Suitable examples of materials for the second metallic layer 52 and the third metallic layer 54 include, but are not limited to, nickel, iron, cobalt, stainless steel, aluminum, copper, magnesium, gold, platinum, MCrAlY, wherein M is Ni, Co, Fe, or combinations thereof, alloys thereof, and combinations thereof. In an embodiment where the thermally-responsive features 20 deploy from the surface 13 (for example, in the raising direction 32), the first metallic layer 50 and/or the second metallic layer 52 have higher coefficients of thermal expansion than the coefficient of thermal expansion for the third metallic layer 54 and/or adjust in the raising direction 32 upon the predetermined temperature change being an increase in temperature. In an embodiment where the thermally-responsive features 20 retract toward the surface 13, (for example, in the retracting direction 34), the first metallic layer 50 and/or the second metallic layer 52 have lower coefficients of thermal expansion than the coefficient of thermal expansion for the third metallic layer 54 and/or adjust in the retracting direction 34 upon the predetermined temperature change being an increase in temperature.

Referring to FIG. 3, in one embodiment, protrusions 57 are positioned on the thermally-responsive features 20. The protrusions 57 are formed by any suitable techniques, such as, by laser sculpting the thermally-responsive features 20. In one embodiment, the protrusions 57 are a discontinuous top layer, capable of altering the shape of the thermally-responsive features 20 based upon differing coefficients of thermal expansion. For example, such altering is capable of generating a wavy set of thermally-responsive features 20, increasing turbulence and/or surface thickness.

Referring to FIGS. 4 and 5, in one embodiment, thermally-responsive features 20 are positioned along the surface 13, for example, of the heat transfer components 1010 shown in FIGS. 1-3. The thermally-responsive features 20 deploy from or retract toward the surface 13 in response to a predetermined temperature change, thereby increasing or decreasing turbulation along the surface 13. The increase or the decrease in the turbulation increases or decreases heat transfer between the surface 13 and the flow path 19 adjacent to the surface 13. In one embodiment, the increase or the decrease in the heat transfer is predominantly based upon an increase or decrease in convective heat transfer.

In one embodiment, thermally-responsive features 20 regulate the flow 16 (for example, of air, gas, liquid, coolant, refrigerant, or any other suitable fluid) and/or heat transfer along the flow path 19. For example, by deploying/raising or retracting in response to the predetermined temperature change, the thermally-responsive features 20 increase or decrease resistance along the flow path 19. The increase or decrease in resistance increases or decreases heat transfer. Additionally or alternatively, in one embodiment, the thermally-responsive features 20 are positioned to provide a predetermined flow characteristic along the flow path 19, for example, the turbulent flow 35, the laminar flow 37, the transitional flow (not shown), or a combination thereof. In further embodiments, the thermally-responsive features 20 direct the flow path 19 to spiral, divert, narrow, expand, or a combination thereof.

Referring to FIG. 4, in one embodiment, the surface 13 includes two or more regions configured for operation under different flow conditions. The velocity, acceleration, proportion of the turbulent flow 35, proportion of the laminar flow 37, proportion of the transitional flow (not shown), rate of heat transfer, mixing of components within the flow 16, depth of the boundary layer 33, or a combination thereof, of the flow 16 along the flow path 19 decrease(s) or increase(s) as a result of the thermally-responsive features 20 being deployed or retracted, thereby increasing or decreasing the surface area of the thermally-responsive features 20. In one embodiment, the surface 13 includes a first region 402 configured for operation under predetermined flow conditions, such as a slower axial flow rate along the flow path 19, for example, due to a greater proportion of the flow 16 being the turbulent flow 35 in comparison to a second region 404 configured for operation under predetermined flow conditions, such as a faster axial flow rate along the flow path 19, for example, due to a lower proportion of the flow being the turbulent flow 35. In a further embodiment, the surface 13 includes a third region 406 with an axial flow rate that is faster than the axial flow rate within the second region, for example, due to a lower proportion of the flow 16 being the turbulent flow 35.

In one embodiment, heat transfer results in temperature differences between the first region 402, the second region 404, and/or the third region 406. Suitable temperature differences include, but are not limited to, a range of between about 10° F. and about 100° F., a range of between about 10° F. and about 50° F., a range of between about 10° F. and about 30° F., a range of between about 10° F. and about 20° F., a range of between about 20° F. and about 100° F., a range of between about 30° F. and about 100° F., a range of between about 50° F. and about 100° F., an amount greater than about 10° F., an amount greater than about 30° F., an amount greater than about 50° F., an amount of about 10° F., an amount of about 30° F., an amount of about 50° F., an amount of about 100° F., or any suitable combination, sub-combination, range, or sub-range therein.

Within each of the regions, the thermally-responsive features 20 have a deployment length 408. The deployment length 408 is based upon the temperature proximal to the thermally-responsive feature 20, the materials used in the thermally-responsive feature 20, the arrangement of the materials in the thermally-responsive feature 20, the thickness of the materials in the thermally-responsive feature 20, or a combination thereof, and is capable of increasing or decreasing the depth of the fluid boundary layer 33. In one embodiment, the deployment length 408 of the thermally-responsive features 20 within the first region 402 is greater than the deployment length 408 of the thermally-responsive features 20 within the second region 404. In a further embodiment, the deployment length 408 of the thermally-responsive features 20 within the second region 404 is greater than the deployment length 408 of the thermally-responsive features 20 within the third region 406.

As will be appreciated by those skilled in the art, any suitable number of the regions is included. For example, in some embodiments, four regions, five regions, six regions, seven regions, eight regions, nine regions or more are included. Referring to FIG. 5, in one embodiment, the amount of the regions included correspond to the amount of the thermally-responsive features 20 included (for example, nine of the thermally-responsive features 20 corresponding with a first region 502, a second region 504, a third region 506, a fourth region 508, a fifth region 510, a sixth region 512, a seventh region 514, an eighth region 516, a ninth region 518). In one embodiment, the thermally-responsive features 20 create a substantially continuous decrease in the deployment lengths 408, for example, capable of increasing or decreasing the velocity, the acceleration, the proportion of the turbulent flow 35, the proportion of the laminar flow 37, the proportion of the transitional flow, the rate of the heat transfer, mixing of components, the depth of the fluid boundary layer 33, or a combination thereof.

The deployment length(s) 408 are any suitable length capable of resulting in a predetermined temperature profile. In one embodiment, the deployment length 408 for one of the thermally-responsive features 20 is between 1 and 10 times greater than the deployment length 408 for another of the thermally-responsive features 20, whether the thermally-responsive features 20 are adjacent or separated by one or more other thermally-responsive features 20. Other suitable differences in the deployment length 408 of one of the thermally-responsive features 20 and another of the thermally-responsive features 20 include, but are not limited to, being 1 time greater, 1.2 times greater, 1.4 times greater, 1.6 times greater, 3 times greater, 5 times greater, 7 times greater, 10 times greater, or any suitable combination, sub-combination, range, or sub-range therein. Additionally or alternatively, in one embodiment, the deployment length 408 of one or more of the thermally-responsive features 20 is between about 0.01 inches and about 0.125 inches, between about 0.01 inches and about 0.05 inches, between about 0.01 inches and about 0.1 inches, between about 0.05 inches and about 0.125 inches, between about 0.08 and about 0.125 inches, between about 0.1 inches and about 0.125 inches, about 0.1 inches, about 0.05 inches, about 0.08 inches, about 0.1 inches, about 0.125 inches, or any suitable combination, sub-combination, range, or sub-range therein.

In addition to the deployment length 408, the thermally-responsive features 20 include a length defined by a portion 410 applied to or integral with the surface 13. In embodiments with the length of the thermally-responsive features 20 being consistent or substantially consistent among the thermally-responsive features 20, the thermally-responsive features 20 with the deployment length 408 being longer include the portion 410 being shorter in comparison to the thermally-responsive features 20 with the deployment length 408 being shorter. Alternatively, in embodiments with the length of the thermally-responsive features 20 differing among the thermally-responsive features 20, for example, increasing/decreasing along the path of the flow path 19, the portion 410 applied to or integral with the surface 13 differs accordingly.

Referring to FIG. 6, in one embodiment, the thermally-responsive features 20 are positioned on the surface 13 of a heat exchanger 602, such as a shell and tube heat exchanger, a plate heat exchanger, a plate and shell heat exchanger, an adiabatic wheel heat exchanger, a plate fin heat exchanger, a pillow plate heat exchanger, a fluid heat exchanger, waste heat recovery unit, a dynamic scraped surface heat exchanger, a phase-change heat exchanger, or any other suitable heat exchanger. As the flow 16 travels through the heat exchanger 602 along the flow path 19, the thermally-responsive features 20 deploy or refract, permitting an increase or decrease in the rate of heat transfer between the flow 16 and the surface 13.

Referring to FIG. 7, in one embodiment, the thermally-responsive features 20 are positioned on the surface 13 of a condenser 702, such as a surface condenser or shell and tube heat exchanger, a Liebig condenser, a Graham condenser, an Allihn condenser, or any other suitable condenser. As the flow 16 travels through the condenser 702 along the flow path 19, the thermally-responsive features 20 deploy or retract, permitting an increase or decrease in the rate of heat transfer between the flow 16 and the surface 13.

Referring to FIG. 8, in one embodiment, the thermally-responsive features 20 are positioned on the surface 13 of a heat pipe 802, such as a thin planar heat pipe or heat spreader, a tubular heat pipe, a one-dimensional tubular heat pipe, a two-dimensional heat pipe, a loop heat pipe, or any other suitable heat pipe. As the flow 16 travels through the heat pipe 802 along the flow path 19, the thermally-responsive features 20 deploy or retract, permitting an increase or decrease in the rate of heat transfer between the flow 16 and the surface 13.

Referring to FIG. 9, in one embodiment, the thermally-responsive features 20 are positioned on the surface 13 of a regenerator 902, such as a rotary regenerator, a fixed matrix regenerator, a micro scale regenerative heat exchanger, a Rothemuhle regenerator, or any other suitable regenerator. As the flow 16 travels through the regenerator 902 along the flow path 19, the thermally-responsive features 20 deploy or retract, permitting an increase or decrease in the rate of heat transfer between the flow 16 and the surface 13.

Referring to FIG. 10, in one embodiment, the thermally-responsive features 20 are positioned on the surface 13 of an evaporative cooler 1002, such as a direct evaporative cooler or open circuit evaporative cooler, an indirect evaporative cooler or closed circuit evaporative cooler, a two-stage evaporative cooler or indirect-direct evaporative cooler, a hybrid evaporative cooler, or any other suitable evaporative cooler. As the flow 16 travels through the evaporative cooler 1002 along the flow path 19, the thermally-responsive features 20 deploy or refract, permitting an increase or decrease in the rate of heat transfer between the flow 16 and the surface 13.

In one embodiment, the heat transfer component 1010 is positioned in a personal temperature control suit (not shown), such as Space Shuttle Extra vehicular Mobility Units or EMUs, race car driver suits, firefighter gear, motorcycle racer suits, or other suitable personal temperature control suits. In one embodiment, the personal temperature control suit includes a network of small diameter water circulation tubes having the thermally-responsive features 20. The tubes are held close to a body by an elastic body suit, configured for heat to be released by body movements and transferred to water in the water circulation tubes that is transported to a refrigeration unit, for example, in a backpack of the personal temperature control suit. In this embodiment, the water contacts the heat transfer component 1010, which is a porous metal plate that is exposed to the vacuum of outer space on the other side. Small amounts of the water pass through the pores and freeze on the outside of the porous metal plate. As additional heated water runs across the plate, the heat is absorbed by aluminum in the metal plate and is conducted to the exposed side. There the ice begins to sublimate, or turn directly into water vapor and disperses in space, thereby cooling. Additional water passes through the pores, and freezes in a similar manner. Consequently, the water flowing across the plate is cooled again and used to recirculate through the suit to absorb more heat. In one embodiment, the personal temperature control suit is supplemented with an air circulation system (not shown) that draws perspiration-laden air from the suit into a water separator. The water is added to the cooling water reservoir while the drier air is returned to the suit. Both the cooling system and the air circulation system work together to contribute to a comfortable internal working environment. In a further embodiment, the thermally-responsive features 20 deploy or retract based upon heat from the body with the personal temperature control suit to control a heat transfer rate.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. 

What is claimed is:
 1. A heat transfer component, comprising: thermally-responsive features positioned along a surface of the heat transfer component; wherein the thermally-responsive features deploy from or retract toward the surface in response to a predetermined temperature change; wherein the deploying from or the retracting toward of the thermally-responsive features increases or decreases a rate of heat transfer between a flow along the surface and the surface.
 2. The heat transfer component of claim 1, wherein the deploying of the thermally-responsive features increases or decreases turbulation of the flow.
 3. The heat transfer component of claim 1, wherein the heat transfer component is a heat exchanger.
 4. The heat transfer component of claim 1, wherein the heat transfer component is a condenser.
 5. The heat transfer component of claim 1, wherein the heat transfer component is a heat pipe, a regenerator, or an evaporative cooler.
 6. The heat transfer component of claim 1, wherein the heat transfer component is a personal temperature control suit.
 7. The heat transfer component of claim 1, wherein a deployment length of one or more of the thermally-responsive features is between about 0.01 inches and about 0.125 inches.
 8. The heat transfer component of claim 1, wherein the thermally-responsive features include a first metallic layer and a second metallic layer.
 9. The heat transfer component of claim 1, wherein one or both of the first metallic layer and the second metallic layer include material selected from the group consisting of nickel, iron, cobalt, stainless steel, aluminum, copper, magnesium, gold, platinum MCrAlY, and combinations thereof.
 10. The heat transfer component of claim 1, wherein the deploying of the thermally-responsive features increases or decreases depth of a boundary layer adjacent the surface.
 11. The heat transfer component of claim 1, wherein the increase or the decrease in the rate of heat transfer is predominantly based upon an increase or decrease in a proportion of convective heat transfer.
 12. The heat transfer component of claim 1, wherein the deploying of the thermally-responsive features increases or decreases the velocity of the flow.
 13. The heat transfer component of claim 1, wherein the deploying of the thermally-responsive features increases or decreases the acceleration of the flow.
 14. The heat transfer component of claim 1, wherein the deploying of the thermally-responsive features increases or decreases a proportion of turbulent flow within the flow.
 15. The heat transfer component of claim 1, wherein the deploying of the thermally-responsive features increases or decreases a proportion of laminar flow within the flow.
 16. The heat transfer component of claim 1, wherein the deploying of the thermally-responsive features increases or decreases a proportion of transitional flow within the flow.
 17. The heat transfer component of claim 1, wherein the deploying of the thermally-responsive features increases or decreases mixing of components of the flow.
 18. A heat exchanger, comprising: thermally-responsive features positioned along a surface of the heat exchanger, the thermally-responsive features having a first metallic layer and a second metallic layer; wherein the thermally-responsive features deploy from or retract toward the surface in response to a predetermined temperature change; wherein the deploying from or the retracting toward of the thermally-responsive features increases or decreases turbulation of a flow along the surface, thereby increasing or the decreasing velocity of the flow, acceleration of the flow, a proportion of turbulent flow within the flow, a proportion of laminar flow within the flow, a proportion of transitional flow within the flow, depth of a boundary layer adjacent to the surface, or a combination thereof.
 19. A heat transfer process, comprising: providing a heat transfer component having thermally-responsive features positioned along a surface of the heat transfer component; and increasing or decreasing a rate of heat transfer between the surface and a flow by deploying the thermally-responsive features from or the retracting the thermally-responsive features toward the surface in response to a predetermined temperature change.
 20. The heat transfer process of claim 1, further comprising increasing or decreasing depth of a boundary layer adjacent to the surface. 